The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component that can be created using a fabrication process) has decreased.
Such advances have increased the complexity of processing and manufacturing ICs. For these advances, similar developments in IC processing and manufacturing are developed accordingly. Along with the advantages realized from reducing geometric size, improvements are being made directly to the IC devices. However, since the feature sizes continue to decrease, fabrication processes continue to become more difficult to perform.
Therefore, it is a challenge to form reliable semiconductor devices with smaller and smaller sizes.